I have brought batteries back from Singapore on Sri Lankan and Qatar Airways. Both times I declare that I have lipos in my hand carry. They checked and allowed me on the plane with the batteries.

Another incident I heard from a friend coming back from Dubai. Although he was flying Qatar Airways which allowed him to take the batteries, the security in Dubai airport refused to let him take the batteries. When he told the security that Qatar Airways said ok, the security said "I have the last say and I say you cannot take it." Hmm maybe he needed some lipos.